Self-luminous display device, control method of self-luminous display device, and computer program

ABSTRACT

Provided is a self-luminous display device including a data calculation section configured to calculate, by using a supplied video signal, data relating to a luminance amount accumulated in a unit of a first block in a target region for luminance control in a screen on which a plurality of pixels are arranged in a matrix, each of the pixels including a light emitting element which emits light by itself according to a current amount, a resampling section configured to resample the data relating to the luminance amount in the target region, in a unit of a second block, the data relating to the luminance amount being calculated by the data calculation section, the second block being larger than the first block, and a scaling section configured to generate data for luminance control in the target region by scaling the data resampled by the resampling section.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Priority PatentApplication JP 2012-283321 filed Dec. 26, 2012, the entire contents ofwhich are incorporated herein by reference.

BACKGROUND

The present disclosure relates to a self-luminous display device, acontrol method of a self-luminous display device, and a computerprogram.

Liquid crystal display devices using liquid crystals and plasma displaydevices using plasma have been implemented as thin display devices witha flat plane.

A liquid crystal display device is a display device including abacklight which displays images by changing an arrangement of liquidcrystal molecules by the application of a voltage, and by allowing lightto pass from the backlight and shielding the light. Further, a plasmadisplay device is a display device which displays images by having aplasma state by applying a voltage to a gas enclosed within a substrate,and by making ultraviolet light, which is generated by energy occurringat the time when returning to an original state from the plasma state,visible light by irradiating on a fluorescent body.

On the other hand, development has been progressing in recent years forself-luminous type display devices using organic EL (electroluminescence) elements which emit light by the elements themselves whena voltage is applied. An organic EL element changes from a ground stateto an excited state when energy is received by electrodes, anddischarges the energy of a difference when returning from the excitedstate to the ground state. An organic EL display device is a displaydevice which displays images by using the light discharged by theseorganic EL elements.

A self-luminous type display device is different to a liquid crystaldisplay device in which a backlight is necessary, and since is it notnecessary to have a backlight in order for elements to emit light bythemselves, a self-luminous type display device is capable of having athin configuration when compared to that of a liquid crystal displaydevice. Further, since moving image characteristics, viewing anglecharacteristics, color reproductively and the like are superior whencompared to those of a liquid crystal display device, self-luminous typedisplay devices using organic EL elements have been receiving attentionas next generation thin display devices with a flat plane.

However, in organic EL elements, the luminance characteristics willdeteriorate when a voltage is continuously applied, and the luminancewill decrease even if the same current is input. As a result of this, inthe case where the luminance frequency of specific pixels is high, aphenomenon of so-called “image persistence” unfortunately occurs inthese specific pixels, since the luminance characteristics aredeteriorated when compared to the luminance characteristics of the otherpixels.

This image persistence phenomenon also occurs in liquid crystal displaydevices and plasma display devices, and since these display devicesperform image display by applying an alternating voltage, a mechanismwhich adjusts the applied voltage may be necessary. In contrast to this,a method has been adopted in self-luminous type display devices, whichprevents image persistence by controlling the current amount. Forexample, JP 2008-149842A discloses prevention technology of imagepersistence in a self-luminous type display device.

SUMMARY

JP 2008-149842A discloses technology, in a display device includinglight emitting elements which emit light in accordance with a currentamount, such as an organic EL display device, which suppresses an imagepersistence phenomenon of the screen by calculating a luminance amountfrom a video signal and controlling the video signal. While thetechnology disclosed in JP 2008-149842A controls the luminance of theentire screen for suppressing an image persistence phenomenon of thescreen, more flexible luminance control is sought after for suppressingan image persistence phenomenon.

Accordingly, the present disclosure provides a new and improvedself-luminous display device capable of suppressing an image persistencephenomenon of a screen by calculating a luminance amount from a videosignal and flexibly controlling the video signal.

According to an embodiment of the present disclosure, there is provideda self-luminous display device including a data calculation sectionconfigured to calculate, by using a supplied video signal, data relatingto a luminance amount accumulated in a unit of a first block in a targetregion for luminance control in a screen on which a plurality of pixelsare arranged in a matrix, each of the pixels including a light emittingelement which emits light by itself in accordance with a current amount,a resampling section configured to resample the data relating to theluminance amount in the target region, in a unit of a second block, thedata relating to the luminance amount being calculated by the datacalculation section, the second block being larger than the first block,and a scaling section configured to generate data for luminance controlin the target region by scaling the data resampled by the resamplingsection in the unit of first block.

According to an embodiment of the present disclosure, there is provideda self-luminous display device including a data calculation sectionconfigured to calculate data relating to a luminance amount accumulatedin a unit of a first block in a target region for luminance control in ascreen on which a plurality of pixels are arranged in a matrix and animage is displayed with a red pixel, a green pixel, a blue pixel, and awhite pixel, each of the pixels including a light emitting element whichemits light by itself in accordance with a current amount, and a signalprocessing section configured to execute signal processing on a videosignal supplied to the screen based on a peak of the data relating tothe luminance amount calculated by the data calculation section.

According to an embodiment of the present disclosure such as describedabove, a new and improved self-luminous display device can be providedcapable of suppressing an image persistence phenomenon of a screen bycalculating a luminance amount from a video signal and flexiblycontrolling the video signal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory diagram which describes a configuration exampleof a self-luminous display device 10 according to an embodiment of thepresent disclosure;

FIG. 2 is an explanatory diagram which shows a configuration example ofa display control section 100;

FIG. 3 is an explanatory diagram which shows an example of an imagedisplayed on the self-luminous display device 10;

FIG. 4 is an explanatory diagram which shows an example of a risk map;

FIG. 5 is an explanatory diagram which shows a configuration example ofa risk and stillness detection section 110;

FIG. 6 is an explanatory diagram which shows a configuration example ofa luminance conversion section 111;

FIG. 7 is an explanatory diagram which shows an example of a peripheralpart of a screen on the organic EL display panel 200;

FIG. 8 is an explanatory diagram which shows an example of large blockdivision of a risk map by a block division section 116;

FIG. 9 is an explanatory diagram which shows a configuration example ofan IIR filter 117;

FIG. 10 is an explanatory diagram which shows a configuration example ofan LPF 118;

FIG. 11 is an explanatory diagram which shows a configuration example ofthe risk and stillness detection section 110 according to an embodimentof the present disclosure;

FIG. 12 is an explanatory diagram which shows an example of a screendivided into blocks when the risk and stillness detection section 110generates a stillness map;

FIG. 13 is an explanatory diagram which shows a configuration example ofa luminance control section 103 and an image persistence preventioncontrol section 104 according to an embodiment of the presentdisclosure;

FIG. 14 is an explanatory diagram which shows a process outline of ahigh luminance suppression gain calculation section 179;

FIG. 15 is an explanatory diagram which shows a process outline of thehigh luminance suppression gain calculation section 179;

FIG. 16 is an explanatory diagram which shows a graph used when athreshold th is obtained by a luminance suppression gain control section171;

FIG. 17 is an explanatory diagram which shows an outline of luminancecontrol by a gain Gall for controlling the luminance of the entirescreen;

FIG. 18 is an explanatory diagram which shows a graph used when theluminance suppression gain control section 171 obtains a gain Gall;

FIG. 19 is an explanatory diagram which shows an outline of luminancecontrol by a gain Ksh_base for controlling a shading ratio for a screenperipheral part;

FIG. 20 is an explanatory diagram which shows an example of a shadingshape stored in an original signal component shading gain LUT 173;

FIG. 21 is an explanatory diagram which shows a graph used when theluminance suppression gain control section 171 obtains a gain Ksh_base;

FIG. 22 is an explanatory diagram which shows, by a graph, a state inwhich a high luminance side of a video signal having a linearcharacteristic is raised to a higher luminance;

FIG. 23 is an explanatory diagram which shows a graph used when theluminance suppression gain control section 171 obtains a gain Gpoff;

FIG. 24 is an explanatory diagram which shows a configuration example ofan IIR filter 176;

FIG. 25 is an explanatory diagram which shows a configuration example ofa WRGB conversion section 105 according to an embodiment of the presentdisclosure;

FIG. 26 is an explanatory diagram which shows a configuration example ofa gain calculation section 214;

FIG. 27 is an explanatory diagram which shows an example of a look-uptable referred to by a gradation-dependent gain calculation section 221;

FIG. 28 is an explanatory diagram which shows a graph used when arisk-linked gain calculation section 223 obtains a gain Gw3; and

FIG. 29 is an explanatory diagram which shows an example of a look-uptable referred to by the gradation-dependent gain calculation section221.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

Hereinafter, preferred embodiments of the present disclosure will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the appended drawings, structural elementsthat have substantially the same function and structure are denoted withthe same reference numerals, and repeated explanation of thesestructural elements is omitted.

The description will be given in the following order.

<1. The embodiments of the present disclosure>

[Configuration example of the self-luminous display device]

[Configuration example of the display control section]

[Configuration example of the risk and stillness detection section]

[Example of luminance control and image persistence prevention control]

[Example of the WRGB conversion process using a risk map for partialcontrol]

<2. Conclusion>

1. THE EMBODIMENTS OF THE PRESENT DISCLOSURE Configuration Example ofthe Self-Luminous Display Device

First, a configuration example of a self-luminous display deviceaccording to an embodiment of the present disclosure will be describedwhile referring to the figures. FIG. 1 is an explanatory diagram whichdescribes a configuration example of a self-luminous display device 10according to an embodiment of the present disclosure. Hereinafter, aconfiguration example of the self-luminous display device 10 accordingto an embodiment of the present disclosure will be described by usingFIG. 1.

The self-luminous display device 10 shown in FIG. 1 is a device whichdisplays a video on an organic EL display panel 200 using organic ELelements which emit light by the elements themselves when a voltage isapplied. As shown in FIG. 1, the self-luminous display device 10according to an embodiment of the present disclosure includes a displaycontrol section 100 and the organic EL display panel 200. When thesupply of a video signal is received, the self-luminous display device10 analyses this video signal, and displays a video via the organic ELdisplay panel 200, by lighting pixels arranged within the organic ELdisplay panel 200 in accordance with the analyzed contents.

The display control section 100 supplies, to the organic EL displaypanel 200, signals for displaying a video on the organic EL displaypanel 200, by applying signal processing to the video signal supplied tothe self-luminous display device 10. For example, the signal processingexecuted by the display control section 100 is a process which controlsthe luminance at the time when performing display, or is an imagepersistence prevention process for preventing image persistence of thescreen on the organic EL display panel 200. A detailed configuration ofthe display control section 100 will be described later.

The organic EL display panel 200 is a display panel using organic ELelements which emit light by the elements themselves when a voltage isapplied such as described above, and has a configuration in which thepixels of the organic EL elements are arranged in a matrix shape. Whilenot illustrated in FIG. 1, the organic EL display panel 200 has aconfiguration, in which scanning lines which select pixels in aprescribed scanning period, data lines which provide luminanceinformation for driving the pixels, and pixel circuits which control thecurrent amount based on the luminance information and allow the organicEL elements to emit light by light emitting elements in accordance withthe current amount, are arranged in a matrix, and by having such aconfiguration of the scanning lines, data lines and pixel circuits, theself-luminous display device 10 can display a video in accordance with avideo signal.

The organic EL display panel 200 according to an embodiment of thepresent disclosure may be a display panel which displays images with thethree primary colors of R (red), G (green) and B (blue), or may be adisplay panel which displays images with four colors which includes W(white) in addition to the three primary colors. In the followingdescription, the organic EL display panel 200 according to an embodimentof the present disclosure will be described as a display panel whichdisplays images with the four colors of R, G, B, W.

Heretofore, a configuration example of the self-luminous display device10 according to an embodiment of the present disclosure has beendescribed by using FIG. 1. Next, a configuration example of the displaycontrol section 100 included in the self-luminous display device 10according to an embodiment of the present disclosure will be described.

[Configuration Example of the Display Control Section]

FIG. 2 is an explanatory diagram which shows a configuration example ofthe display control section 100 included in the self-luminous displaydevice 10 according to an embodiment of the present disclosure.Hereinafter, a configuration example of the display control section 100included in the self-luminous display device 10 according to anembodiment of the present disclosure will be described by using FIG. 2.

The display control section 100 shown in FIG. 2 executes signalprocessing on a video signal of each of the three supplied colors R(red), G (green) and B (blue). As shown in FIG. 2, the display controlsection 100 included in the self-luminous display device 10 according toan embodiment of the present disclosure includes an orbit circuit 101, alinear gamma circuit 102, a luminance control section 103, an imagepersistence prevention control section 104, a WRGB conversion section105, and a risk and stillness detection section 110.

The orbit circuit 101 performs signal processing (an orbit process) forblurring the edges of a supplied video signal. Specifically, in order toprevent an image persistence phenomenon of an image on the organic ELdisplay panel 200, the orbit circuit 101 executes a process whichsuppresses an image persistence phenomenon of the image by allowing theentire image displayed on the organic EL display panel 200 toperiodically deviate up-down and left-right, at a slow speed to theextent that a viewer will not comprehend it. The orbit circuit 101supplies the video signal to which the orbit process has been executedto the linear gamma circuit 102 and the risk and stillness detectionsection 110.

The linear gamma circuit 102 performs signal processing to convert avideo signal, in which the output for an input has a gammacharacteristic, so as to have a linear characteristic from the gammacharacteristic. By performing signal processing in the linear gammacircuit 102 so that the output for an input has a linear characteristic,various processes for an image displayed on the organic EL display panel200 become easy. The linear gamma circuit 102 supplies the signal afterconversion to the overall luminance control section 103.

The luminance control section 103 executes a gain process forcontrolling the luminance when displaying a video on the organic ELdisplay panel 200, for the video signal converted in the linear gammacircuit 102 so as to have a linear characteristic. The luminance controlsection 103 executes a gain process for a video signal which has aluminance equal to or more than a prescribed level, for example, so thatthe luminance becomes equal to or less than the prescribed level. Theluminance control section 103 supplies the video signal after the gainprocess has been executed to the image persistence prevention controlsection 104.

The image persistence prevention control section 104 executes luminancecontrol for preventing image persistence, in the case where there is thepossibility of image persistence occurring on the organic EL displaypanel 200, for the video signal after the gain process has beenperformed by the luminance control section 103. The image persistenceprevention control section 104 uses data generated in the risk andstillness detection section 110, when executing luminance control forpreventing image persistence. The data generated in the risk andstillness detection section 110 will be described later. The imagepersistence prevention control section 104 supplies the video signalafter luminance control for preventing image persistence has beenexecuted to the WRGB conversion section 105.

The WRGB conversion section 105 converts the video signal, to whichluminance control for preventing image persistence has been performed bythe image persistence prevention control section 104, into a videosignal for displaying a video with the 4 colors R, G, B, W on theorganic EL display panel 200. The WRGB conversion section 105 uses datagenerated in the risk and stillness detection section 110, whenexecuting a conversion process of the video signal. The video signalconverted by the WRGB conversion section 105 is converted again so as tohave a gamma characteristic when displayed on the organic EL displaypanel 200, and is thereafter supplied to the organic EL display panel200.

The risk and stillness detection section 110 obtains a position, on theorganic EL display panel 200, at which there is a high possibility of animage persistence phenomenon occurring, by using the video signalsupplied from the orbit circuit 101, and outputs this positioninformation to the image persistence prevention control section 104 andthe WRGB conversion section 105. As described above, in organic ELelements, the luminance characteristics will deteriorate when a voltageis continuously applied, and the luminance will decrease even if thesame current is input. As a result of this, in the case where theluminance frequency of specific pixels is high, the luminancecharacteristics of these specific pixels will be deteriorated whencompared to the luminance characteristics of the other pixels. This isthe phenomenon which is called “image persistence”.

The risk and stillness detection section 110 generates information (amap) which specifies the location of the pixels which have a highluminance frequency, by using the video signal output from the orbitcircuit 101. Also, the risk and stillness detection section 110 sends,to the image persistence prevention control section 104, a peak value ofthe degree of risk, which includes the time and luminance at which lighthas been continuously emitted, for the pixels which have a highluminance frequency (a high risk of image persistence). By controllingthe luminance by using a peak value of the degree of risk, the imagepersistence prevention control section 104 can prevent the generation ofan image persistence phenomenon on the organic EL display panel 200.

For example, as shown in FIG. 3, a video which continuously displays thecurrent time on a portion of the screen is supplied to the self-luminousdisplay device 10. Since the time display portion on the upper left inFIG. 3 is displayed at a luminance higher to some extent than thatnormally, there is a high risk of image persistence for the pixels whichdisplay the time, and the degree of risk will rise in accordance withthe passing of time as long as the time is continuously displayed.

Accordingly, the risk and stillness detection section 110 shows that thedegree of risk is rising for the pixels which display the time, bygenerating a risk map such as shown in FIG. 4. While the pixels otherthan those in the time display portion do not have a large rise in thedegree of risk since the displayed image changes, since the degree ofrisk rises in accordance with the passing of time as long as the pixelsof the time display portion continuously display the time, the value ofthe degree of risk will increase in the risk map for the pixels of thetime display portion.

The risk and stillness detection section 110 performs detection of astill image. Since an image persistence phenomenon occurs by thedeterioration of specific pixels when the same still image iscontinuously displayed for a long period of time, the risk and stillnessdetection section 110 obtains a parameter called the degree ofstillness, which is similar to the above described degree of risk, andgenerates information (a map) which specifies the location of the pixelswhich have a high luminance frequency.

Also, the risk and stillness detection section 110 sends, to the imagepersistence prevention control section 104, a peak value of the degreeof stillness, which includes the time and luminance at which light hasbeen continuously emitted, for the pixels which have a high luminancefrequency (a high risk of image persistence). By controlling theluminance by using a peak value of the degree of stillness, the imagepersistence prevention control section 104 can prevent the generation ofan image persistence phenomenon on the organic EL display panel 200.

The generation of a risk map and a stillness map in the risk andstillness detection section 110 are not processes for one pixel unit.Therefore, the risk and stillness detection section 110 generates a riskmap and a stillness map, by detecting the video signal after an orbitprocess has been performed by the orbit circuit 101.

By considering not only the case where the luminance of the entirescreen is controlled for preventing image persistence, but also the casewhere the luminance is controlled for a portion of the screen forpreventing image persistence, the risk and stillness detection section110 generates a risk map for partial control, in the image persistenceprevention control section 104, for controlling a portion of the screen.By generating a risk map for partial control by the risk and stillnessdetection section 110, the image persistence prevention control section104 can control luminance without having an impact on the image quality,for a portion of the screen, in order to prevent image persistence.

When a risk map for partial control is generated, the risk and stillnessdetection section 110 supplies this risk map for partial control to theWRGB conversion section 105 as well as to the image persistenceprevention control section 104. By using a risk map for partial control,the WRGB conversion section 105 is capable of performing luminancecontrol, for a portion of the screen, when converting a video with thefour colors R, G, B, W into a video signal for displaying on the organicEL display panel 200.

Note that while not shown in FIG. 2, a circuit for reconverting thevideo signal, which has been converted so as to have a linearcharacteristic in the linear gamma circuit 102, in order to display avideo on the organic EL display panel 200, may be included in a laterstage of the WRGB conversion section 105.

Heretofore, a configuration example of the display control section 100included in the self-luminous display device 10 according to anembodiment of the present disclosure has been described by using FIG. 2.Next, a configuration example of the risk and stillness detectionsection 110 according to an embodiment of the present disclosure will bedescribed.

[Configuration Example of the Risk and Stillness Detection Section]

FIG. 5 is an explanatory diagram which shows a configuration example ofthe risk and stillness detection section 110 according to an embodimentof the present disclosure. The explanatory diagram shown in FIG. 5 is aconfiguration example of the risk and stillness detection section 110for generating a risk map. Hereinafter, a configuration example of therisk and stillness detection section 110 according to an embodiment ofthe present disclosure will be described by using FIG. 5.

As shown in FIG. 5, the risk and stillness detection section 110according to an embodiment of the present disclosure includes aluminance conversion section 111, a high luminance determination section112, a risk map updating section 113, a risk map storage section 114, amaximum value detection section 115, a block division section 116, anIIR filter 117, a low-pass filter (LPF) 118, and an enlargement scalingsection 119.

The luminance conversion section 111 obtains a luminance of each colorfor a video signal supplied to the risk and stillness detection section110, and supplies an additional luminance L for the color which has amaximum luminance to the high luminance determination section 112.

FIG. 6 is an explanatory diagram which shows a configuration example ofthe luminance conversion section 111. As shown in FIG. 6, the luminanceconversion section 111 includes multipliers 121 a, 121 b, 122 a, 122 b,123 a and 123 b, an adder 124, and a maximum value selection section125.

The multiplier 121 a is included for converting to signals in order toobtain a white luminance along with the other colors, by multiplying aprescribed coefficient Lr1 for a red video signal R_(in). Similarly, themultiplier 122 a multiplies a prescribed coefficient Lg1 for a greenvideo signal G_(in), and the multiplier 123 a multiplies a prescribedcoefficient Lb1 for a blue video signal B_(in). The adder 124 adds theoutputs from the multipliers 121 a, 122 a and 123 a, and outputs theaddition result.

The multiplier 121 b is included in order to convert to a signal forobtaining a red monochrome luminance, by multiplying a prescribedcoefficient Lr2 by the red video signal R_(in). Similarly, themultiplier 122 b multiplies a prescribed coefficient Lg2 by the greenvideo signal G_(in), and the multiplier 123 b multiplies a prescribedcoefficient Lb2 by the blue video signal B_(in).

The processes by the multipliers 121 a, 121 b, 122 a, 122 b, 123 a and123 b and the adder 124 are represented by the following equations.

L _(W) =Rin*Lr1+Gin*Lg1+Bin*Lb1

L _(R) =Rin*Lr2

L _(G) =Gin*Lg2

L _(B) =Bin*Lb2

The maximum value selection section 125 selects the maximum value fromamong L_(W), L_(R), L_(G) and L_(B) obtained by the above describedequations, and outputs the maximum value as a luminance L_(out). Theprocess of the maximum value selection section 125 is represented by thefollowing equation.

L _(out)=Max(L _(W) ,L _(R) ,L _(G) ,L _(B))

The high luminance determination section 112 outputs, to the risk mapupdating section 113, a map updating determination value of whether ornot a risk map generated by the risk map updating section 113 isupdated, by performing a threshold determination of luminance inprescribed block units for the luminance L output from the luminanceconversion section 111. In the present embodiment, the high luminancedetermination section 112 divides one screen into blocks of 8×8 pixelunits, and performs a threshold determination of luminance by these unitblocks. For example, a relation example between the luminance and thedetermination value is represented as follows in the case where fourthresholds (th1, th2, th3 and th4) are included.

if (L>th1)Jv=p _(—) r1

elseif (L>th2)Jv=p _(—) r2

elseif (L>th3)Jv=p _(—) r3

elseif (L>th4)Jv=p _(—) r4

else Jv=p _(—) r5

In the above described relation example, p_r1˜p_r5 are parameters, andare values capable of being set in a range of −255˜+255, for example.

The risk map updating section 113 generates and updates the risk map byusing the map updating determination value supplied from the highluminance determination section 112. In the present embodiment, historydata is generated by having the determination value added in blockunits. The data length of this history data is 8 bits per one block.Also, in the present embodiment, a risk map for the entire screen isgenerated by this history data. The risk map updating section 113 storesthe generated and updated risk map in the risk map storage section 114.Further, when the risk map is updated, the risk map updating section 113supplies the updated risk map to the maximum value detection section115.

The risk map updating section 113 adds the determination value suppliedfrom the high luminance determination section 112 to each of the blocks.That is, the history data increases if the determination value suppliedfrom the high luminance determination section 112 is a positive value,and the history data decreases if the determination value is a negativevalue. If it is assumed that the history data of the current point isriskmap (x,y), the history data immediately prior is riskmap_old (x,y),and the determination value of the current point is Jv (x,y), riskmap(x,y) can be obtained by the following equation. Note that x,y showsboth the horizontal and the vertical block positions.

riskmap(x,y)=riskmap_old(x,y)+Jv(x,y)

Note that if the determination value is a positive value, the risk mapupdating section 113 updates the risk map at a set updating interval. Onthe other hand, if the determination value is a negative value, the riskmap updating section 113 immediately updates the risk map withoutdepending on a setting parameter of the updating interval, and resetsthe degree of risk for this block to 0. That is, it may be necessary forthe determination value to be a positive value over a long period oftime, in order for the degree of risk to be counted up. A plurality ofupdating interval parameters may be retained so as to be capable ofseparating cases in accordance with the value of the degree of risk.Hereinafter, setting examples of updating interval parameters are shown.

Degree of risk 0˜r1: update1 <For time control up to the start ofmultiplying the gain process>

Degree of risk r1˜r2: update2 <For time control during the time ofmultiplying the gain process>

Degree of risk r2˜r3: update3 <For time control up to a second gainprocess>

Degree of risk r3˜r4: update4 <For time control during the time of thesecond gain process>

The risk map updating section 113 may update the risk map at an intervalset by the above described update1˜update4. Note that, since it isassumed to be a process of partial units, the updating intervalparameter is capable of being set at 20 bits.

Note that, only in the case where the degree of risk is counted up from0 may the risk map updating section 113 immediately reflect this in therisk map without depending on an updating interval parameter. This isbecause the case where the value is 0 is a state in which the degree ofrisk is has been reset.

The maximum value detection section 115 detects the maximum value in therisk map updated by the risk map updating section 113, and outputs thismaximum value. In the present embodiment, the maximum value detectionsection 115 outputs the maximum value of the degree of risk for theentire screen, and the maximum value of the degree of risk for aperipheral part of the screen. FIG. 7 is an explanatory diagram whichshows an example of a peripheral part of the screen on the organic ELdisplay panel 200. The maximum value detection section 115 outputs themaximum value of the degree of risk for the entire screen, and themaximum value of the degree of risk for a peripheral part of the screenA1. Note that, the range of the peripheral part of the screen A1 iscapable of being changed by a setting of a register.

In this way, since not only the maximum value of the degree of risk forthe entire screen, but also the maximum value of the degree of risk forthe peripheral part of the screen is output by the maximum valuedetection section 115, image persistence is likely to occur, inparticular, in the peripheral part of the screen. There are many caseswhere information, such as the current time shown in FIG. 3 orsubtitles, are displayed on the peripheral part of the screen.Therefore, by outputting the maximum value of the degree of risk for theperipheral part of the screen by the maximum value detection section115, it becomes possible to perform luminance control for the peripheralpart of the screen at which image persistence is likely to occur.

The block division section 116 divides the risk map supplied from therisk map updating section 113 into blocks of a large size (large blocks)by integrating a plurality of the blocks of the risk map. The blockdivision section 116 divides the risk map generated by units of 8pixels×8 pixels, for example, into large blocks of a size of 16pixels×16 pixels. Note that, the division units by the block divisionsection 116 are capable of being changed by a setting.

FIG. 8 is an explanatory diagram which shows an example of large blockdivision of the risk map by the block division section 116. Thereference numeral 130 shown on the left side of FIG. 8 is a risk mapgenerated by units of 8 pixels×8 pixels, for example, and the referencenumeral 131 represents one block in the risk map. Also, the referencenumeral 132 shown on the right side of FIG. 8 is a state in which therisk map represented by the reference numeral 130 is divided into largeblocks, so that one large block 133 becomes a size of 16 pixels×16pixels.

Also, when the risk map is divided into large blocks, the block divisionsection 116 searches for the maximum value of the degree of risk, bysetting each of the large blocks and the 8 large blocks surrounding eachof these large blocks as a target, and outputs this maximum value. The 9large blocks represented by the reference numeral 134 in FIG. 8 becomesthe search range of a maximum value of the degree of risk for the largeblock represented by the reference numeral 133.

Note that, in the case where the search range protrudes outside of thescreen, the block division section 116 sets this protruding range as asearch range excluded from the range to be searched. Further, while thedivision units by the block division section 116 are capable of beingchanged by a setting, there may be cases where the boundaries of thelarge blocks divided by the block division section 116 and theboundaries of the blocks of the risk map do not match each other, as aresult of being updated. In this case, a search may be performed byhaving the blocks of the risk map on the boundaries of the large blocks,which are divided by the block division section 116, superimposed ondifferent large blocks.

The IIR filter 117 is an IIR filter applied to the maximum value of thedegree of risk for each block searched for by the block division section116. The IIR filter 117 applies an IIR filter which is expressed by thefollowing equation.

Y _(n) =X _(n) +K(ΔX _(n))*(Y _(n-1) −X _(n))

FIG. 9 is an explanatory diagram which shows a configuration example ofthe IIR filter 117 for implementing the above described equation. Asshown in FIG. 9, the IIR filter 117 includes a selector 141, adders 142and 144, a multiplier 143, and a delayer 145.

The selector 141 selects one value out of the two values (iir_rate_p,iir_rate_m) in accordance with a positive value of the differencebetween frames for each block in the adder 142, and outputs the selectedvalue as a feedback ratio K. The adder 142 subtracts an input valueX_(n) of the current frame from an output value Y_(n-1) of the previousframe, and outputs the subtraction result. The multiplier 143 multipliesthe feedback ratio K output from the selector 141 by the output of theadder 142 (Y_(n-1)−X_(n)), and outputs the multiplication result. Theadder 144 multiplies the output of the multiplier 143 by the input valueX_(n) of the current frame, and outputs the multiplication result. Thedelayer 145 outputs the output of the adder 144 to the adder 142 with aone frame delay.

The LPF 118 applies an LPF for both a horizontal direction and avertical direction to the output of the IIR filter 117, and outputs theapplied LPF to the enlargement scaling section 119. FIG. 10 is anexplanatory diagram which shows a configuration example of the LPF 118.As shown in FIG. 10, the LPF 118 includes a horizontal LPF 151 whichapplies an LPF to the horizontal direction, and a vertical LPF 152 whichapplies an LPF to the vertical direction.

Note that a tap number of 3 taps or 5 taps is capable of being selectedfor the horizontal LPF 151 and the vertical LPF 152 shown in FIG. 10.

The enlargement scaling section 119 executes a process, for the outputof the LPF 118, which enlarges the value of the degree of risk retainedin the large block units into pixel units. The enlargement scalingsection 119 performs linear interpolation between the large blocks, whenenlarging the value of the degree of risk into pixel units. Further, theenlargement scaling section 119 may be configured to be capable ofselecting, for the process at the screen edge parts, whether to performextrapolation or whether to retain the values of the large blocks.

Note that, since the division unit of large blocks by the block divisionsection 116 is capable of being changed by a setting, the enlargementscaling section 119 performs linear interpolation for the value of thedegree of risk by using and multiplying parameters corresponding to adivision process.

In this way, the risk and stillness detection section 110 generates arisk map for partial control, by dividing the risk map into large blockunits, and thereafter passing through the IIR filter 117 and the LPF 118and performing linear interpolation by the enlargement scaling section119. By generating such a risk map for partial control, the risk andstillness detection section 110 can execute luminance control forpreventing image persistence for some portion of the screen, so that adifference in luminance with the other portions is not prominent.

The block division section 116, the IIR filter 117 and the LPF 118 shownin FIG. 5 function as an example of a resampling section of the presentdisclosure. That is, the block division section 116 divides the risk mapin block units larger than the blocks to be calculated by the risk mapupdating section 113, and the IIR filter 117 and the LPF 118 performresampling of the risk map divided by the block division section 116.

Up to here, a configuration example of the risk and stillness detectionsection 110 for generating a risk map has been described. To continue, aconfiguration example of the risk and stillness detection section 110for generating a stillness map will be described.

FIG. 11 is an explanatory diagram which shows a configuration example ofthe risk and stillness detection section 110 according to an embodimentof the present disclosure. The explanatory diagram shown in FIG. 11 is aconfiguration example of the risk and stillness detection section 110for generating a stillness map. Hereinafter, a configuration example ofthe risk and stillness detection section 110 according to an embodimentof the present disclosure will be described by using FIG. 11.

As shown in FIG. 11, the risk and stillness detection section 110according to an embodiment of the present disclosure includes aluminance conversion section 111, a stillness determination section 161,a luminance data storage section 162, a stillness map updating section163, a stillness map storage section 164, and a maximum value detectionsection 165.

The luminance conversion section 111 obtains a luminance of each colorfor a video signal supplied to the risk and stillness detection section110, and supplies an additional luminance L for the color which has amaximum luminance to the stillness determination section 161. Aconfiguration example of the luminance conversion section 111 is shownin FIG. 6, for example.

The stillness determination section 161 obtains an average luminance forthe entire screen and an average luminance for each block when thescreen is divided into blocks of a prescribed size, and determines adegree of stillness of a video for each of the blocks. FIG. 12 is anexplanatory diagram which shows an example in which the screen individed into blocks when the risk and stillness detection section 110generates a stillness map. When the risk and stillness detection section110 generates a stillness map, blocks are created by dividing the screeninto 15 blocks in the vertical direction and 30 blocks in the horizontaldirection, such as shown in FIG. 12, for example, and a stillness stateof a video is determined for each of these blocks.

When an average luminance for the entire screen and an average luminancefor each block are obtained, the stillness determination section 161retains information of the average luminance in the luminance datastorage section 162. Note that, it may not be necessary for thestillness determination section 161 to divide strictly by the number ofpixels when obtaining an average luminance, and the average luminancemay be obtained by performing standardization by bit shifting.

Also, the stillness determination section 161 obtains a difference ofthe average luminance with that of the previous frame for each block,and by comparing a threshold determination of the difference values ofthe average luminance with the average luminance for the entire screenand the average luminance for each block, a stillness state of the videois determined, and a determination value is sent to the stillness mapupdating section 163. If the average luminance for the entire screen islow, and the average luminance for the entire screen and the averageluminance for each block are of approximately at the same level, thestillness determination section 161 does not determine that the videohas a stillness state.

A determination process of a stillness state by the stillnessdetermination section 161 will be described in more detail. Adetermination process of a stillness state by the stillnessdetermination section 161 is executed according to the various conditiondetermination processes shown below.

<Condition 1>

The stillness determination section 161 judges whether or not adifference between frames of the average luminance for each block isequal to or less than a threshold th_still. If a difference betweenframes of the average luminance for each block is equal to or less thanthe threshold th_still, the stillness determination section 161 proceedsto the next condition.

<Condition 1-1>

The stillness determination section 161 judges whether or not theaverage luminance for the entire screen is equal to or less than athreshold th_level, and whether or not a difference between the averageluminance for the entire screen and the average luminance for each blockis equal to a threshold th_inout. If this condition is satisfied, thestillness determination section 161 sets a determination value Jv asp_s1(+1).

<Condition 1-2>

In the case where condition 1-1 is not satisfied, the stillnessdetermination section 161 sets the determination value Jv as p_s2(+1 or−255).

<Condition 2>

In the case where condition 1 is not satisfied, the stillnessdetermination section 161 sets the determination value Jv as p_s3(−255).

A determination process of this stillness state by the stillnessdetermination section 161 is represented as follows.

  if((APL_(N-1) − APL_(N)) < th_still){  if((ALL_APL_(N) <th_level)&&(ALL_APL_(N) − APL_(N)) < th_inout)    Jv = p_s1   else    Jv= p_s2 }else    Jv = p_s3

The stillness map updating section 163 generates a stillness map, byupdating the degree of stillness for each block by using thedetermination value determined by the stillness determination section161. The stillness map updating section 163 adds the determinationvalue, retained in each block and determined by the stillnessdetermination section 161, to history data of the degree of stillnessstored in the stillness map storage section 164. The history dataincreases if the determination value determined by the stillnessdetermination section 161 is a positive value, and the history datadecreases if the determination value is a negative value.

The calculation of the history data by the stillness map updatingsection 163 is represented by the following equation. In the followingequation, stillmap(area) is history data in the block of a numberedarea, stillmap_old(area) is history data in the block of a numbered areaprior to updating, and Jv(area) is a determination value in the block ofa numbered area.

stillmap(area)=stillmap_old(area)+Jv(area)

Note that, if the determination value is a positive value, the stillnessmap updating section 163 updates the stillness map stored in thestillness map storage section 164 at a set updating interval. On theother hand, if the determination value is a negative value, thestillness map updating section 163 immediately updates the stillness mapwithout depending on a setting parameter of the updating interval, andresets the degree of stillness for this block to 0. That is, it may benecessary for the determination value to be a positive value over a longperiod of time, in order for the degree of stillness to be counted up. Aplurality of updating interval parameters may be retained so as to becapable of separating cases in accordance with the value of the degreeof stillness. Hereinafter, setting examples of updating intervalparameters are shown.

Degree of stillness 0˜s1: update1 <For time control up to the start ofmultiplying the gain process>

Degree of stillness s1˜s2: update2 <For time control during the time ofmultiplying the gain process>

Degree of stillness s2˜s3: update3 <For time control up to a second gainprocess>

Degree of stillness s3˜s4: update4 <For time control during the time ofthe second gain process>

The stillness map updating section 163 may update the stillness map atan interval set by the above described update1˜update4. Note that, sinceit is assumed to be a process of partial units, the updating intervalparameter is capable of being set at 20 bits.

Note that only in the case where the degree of stillness is counted upfrom 0 may the stillness map updating section 163 immediately reflectthis is the stillness map without depending on an updating intervalparameter. This is because the case where the value is 0 is a state inwhich the degree of stillness has been reset.

The maximum value detection section 165 detects the maximum value in thestillness map updated by the stillness map updating section 163, andoutputs this maximum value. In the present embodiment, the maximum valuedetection section 165 outputs the maximum value of the degree ofstillness in block units, in order to perform luminance control in blockunits.

Heretofore, a configuration example of the risk and stillness detectionsection 110 according to an embodiment of the present disclosure hasbeen described. Next, luminance control and image persistence preventioncontrol, using the risk map or the stillness map generated by the riskand stillness detection section 110, will be described.

[Example of Luminance Control and Image Persistence Prevention Control]

FIG. 13 is an explanatory diagram which shows a configuration example ofthe luminance control section 103 and the image persistence preventioncontrol section 104 according to an embodiment of the presentdisclosure. Hereinafter, a configuration example of the luminancecontrol section 103 and the image persistence prevention control section104 according to an embodiment of the present disclosure will bedescribed by using FIG. 13.

“ux_y_z” shown in FIG. 13 shows that there is y unsigned bit data, thereis an accuracy of z bits, and values can be taken up to x bit times foran input by the application of a gain. That is, “u2_(—)10_(—)6” showsthat there is 10 unsigned bit data, there is an accuracy of 6 bits, andvalues can be taken up to 4 times for the input.

First, a configuration example of the image persistence preventioncontrol section 104 will be described. As shown in FIG. 13, the imagepersistence prevention control section 104 according to an embodiment ofthe present disclosure includes a luminance suppression gain controlsection 171, a raised portion shading gain LUT (Look Up Table) 172, anoriginal signal component shading gain LUT 173, shading strength controlsections 174 and 175, an IIR filter 176, multipliers 177, 178, 180, 181a, 181 b and 181 c, and a high luminance suppression gain calculationsection 179.

The luminance suppression gain control section 171 outputs a value and again used in the luminance control executed by the image persistenceprevention control section 104, by using peak values of the degree ofstillness and the degree of risk for the entire screen or for a portionof the screen, and a risk map for partial control, which are output bythe risk and stillness detection section 110.

In the present embodiment, the luminance suppression gain controlsection 171 calculates a threshold (th) which may be necessary in thecalculation of a gain for high luminance suppression, a gain (Gall) forcontrolling the luminance of the entire screen, and a gain (Ksh_base)for controlling the extent to which the luminance of a screen peripheralpart is lowered (a shading ratio), by using peak values of the degree ofstillness and the degree of risk for the entire screen or for a portionof the screen, and a risk map for partial control. Further, theluminance suppression gain control section 171 obtains a gain (Gpoff)for weakening the gain when performing a process in which an input valueof luminance is increased more than the luminance for a signal equal toor more than a prescribed value (a raising process), by the luminancecontrol section 103. Further, the luminance suppression gain controlsection 171 calculates a gain (Ksh_peak) for controlling the shadingratio of a screen peripheral part, in order to be reflected in the gainGpoff.

The value and the gain calculated by the luminance suppression gaincontrol section 171 will be described in detail in order. First, acalculation of the threshold th which may be necessary for thecalculation of the gain for high luminance restraint, by the luminancesuppression gain control section 171, will be described.

The threshold th is used for the calculation of a gain curve forsuppressing the luminance of the high luminance side, in the highluminance suppression gain calculation section 179. FIG. 14 is anexplanatory diagram which shows a process outline of the high luminancesuppression gain calculation section 179. As shown in FIG. 14,calculating a gain for weakening the luminance of the high luminanceside is a process by the luminance suppression gain calculation section179, when the degree of risk or the degree of stillness increases for avideo signal which has a linear characteristic.

FIG. 15 is an explanatory diagram which shows a process outline of thehigh luminance suppression gain calculation section 179. As shown inFIG. 15, the luminance of the input signal has a gain of 1.0 times from0 up to a prescribed threshold th, for a video signal which has a linearcharacteristic, and when such a gain is applied which decreases by aninclination −a when the threshold th is exceeded, the luminance of thehigh luminance side can be controlled by a two-dimensional curve. Whenthe input is set as x and the output is set as y, the process by thehigh luminance suppression gain calculation section 179 is representedby the following equation.

$y = {{{Gain}*x} = \begin{Bmatrix}{x\mspace{14mu} \ldots \mspace{14mu} \left( {x \leq {th}} \right)} \\{{- {ax}^{2}} + {\left( {1 + {a*{th}}} \right)*x\mspace{14mu} \ldots \mspace{14mu} \left( {x > {th}} \right)}}\end{Bmatrix}}$

The high luminance suppression gain calculation section 179 outputs again Gain to the multiplier 180 so as to satisfy the above describedequation. The multiplier 180 multiplies the gain output from themultiplier 178, which is a is a gain for a shading process which will bedescribed later, by the gain Gain output by the high luminancesuppression gain calculation section 179, and outputs the multiplicationresult to the multipliers 181 a, 181 b and 181 c. The multipliers 181 a,181 b and 181 c suppress the luminance of the high luminance side, bymultiplying the output of the multiplier 180 for the video signal ofeach of R, G and B, and outputting the multiplication result.

The luminance suppression gain control section 171 is the section whichobtains this threshold th. FIG. 16 is an explanatory diagram which showsa graph used when obtaining the threshold th by the luminancesuppression gain control section 171. In the graph shown in FIG. 16, thehorizontal axis is the maximum value for the entire screen in the riskmap generated by the risk and stillness detection section 110, and thevertical axis is the threshold th.

In the case where the maximum value for the entire screen in the riskmap is equal to or less than a prescribed value riskstt2, such as in thegraph shown in FIG. 16, the luminance suppression gain control section171 outputs the threshold th as a prescribed threshold th_ini. Also,when the maximum value for the entire screen in the risk map exceeds theprescribed value riskstt2, the luminance suppression gain controlsection 171 outputs the threshold th lowered from th_ini. The luminancesuppression gain control section 171 lowers the threshold th from th_iniso that the inclination becomes −b.

Also, when the maximum value for the entire screen in the risk mapbecomes a prescribed value riskend2, the luminance suppression gaincontrol section 171 stops the reduction of the threshold th, andthereafter outputs the same value even if the maximum value for theentire screen in the risk map exceeds riskend2.

The process which calculates the threshold th by the luminancesuppression gain control section 171 is represented by the followingequation.

if (riskpeak<riskstt2)th=th _(—) ini

elseif (riskpeak<riskend2)th=th _(—) ini−b*(riskpeak−riskstt2)

else th=th _(—) ini−b*(riskend2−riskstt2)

Note that while a case has been mentioned in the above description whichuses a risk map, the luminance suppression gain control section 171calculates a similar threshold by using a stillness map. Also, theluminance suppression gain control section 171 compares the threshold thobtained by using the risk map with the threshold th obtained by usingthe stillness map, and outputs the lowest threshold to the highluminance control gain calculation section 179.

Heretofore, a calculation of the threshold th which may be necessary forthe calculation of a gain for high luminance control, by the luminancesuppression gain control section 171, has been described. Next, acalculation of the gain Gall for controlling the luminance of the entirescreen, by the luminance suppression gain control section 171, will bedescribed.

FIG. 17 is an explanatory diagram which shows an outline of luminancecontrol by the gain Gall for controlling the luminance of the entirescreen, which is calculated by the luminance suppression gain controlsection 171. As shown in FIG. 17, the luminance suppression gain controlsection 171 calculates the gain Gall for uniformly weakening theluminance, regardless of the input level, when the degree of risk or thedegree of stillness increases, for a video signal which has a linearcharacteristic.

FIG. 18 is an explanatory diagram which shows a graph used whenobtaining the gain Gall by the luminance suppression gain controlsection 171. In the graph shown in FIG. 18, the horizontal axis is themaximum value for the entire screen in the risk map generated by therisk and stillness detection section 110, and the vertical axis is thegain Gall.

In the case where the maximum value for the entire screen in the riskmap is equal to or less than a prescribed value riskstt3, such as in thegraph shown in FIG. 18, the luminance suppression gain control section171 outputs the gain Gall as a prescribed value gall_ini. Also, when themaximum value for the entire screen in the risk map exceeds theprescribed value riskstt3, the luminance suppression gain controlsection 171 outputs the gain Gall lowered from gall_ini. The luminancesuppression gain control section 171 lowers the gain Gall from gall_iniso that the inclination becomes −c.

Also, when the maximum value for the entire screen in the risk mapbecomes a prescribed value riskend3, the luminance suppression gaincontrol section 171 stops the reduction of the gain Gall, and thereafteroutputs the same value even if the maximum value for the entire screenin the risk map exceeds riskend3. The process which calculates the gainGall by the luminance suppression gain control section 171 isrepresented by the following equation.

if (riskpeak<riskstt3)Gall=gall _(—) ini

elseif (riskpeak<riskend3)Gall=gall _(—) ini−c*(riskpeak−riskstt3)

else Gall=gall _(—) ini−c*(riskend3−riskstt3)

Note that while a case has been mentioned in the above description whichuses a risk map, the luminance suppression gain control section 171calculates a similar gain by using a stillness map. Also, the luminancesuppression gain control section 171 compares the gain Gall obtained byusing the risk map with the gain Gall obtained by using the stillnessmap, and outputs the lowest threshold to the multiplier 178.

Heretofore, a calculation of the gain Gall for controlling the luminanceof the entire screen, by the luminance suppression gain control section171, has been described. Next, a calculation of the gain Ksh_base forcontrolling the shading ratio for a screen peripheral part, by theluminance suppression gain control section 171, will be described.

FIG. 19 is an explanatory diagram which shows an outline of luminancecontrol by the gain Ksh_base for controlling the shading ratio for ascreen peripheral part, which is calculated by the luminance suppressiongain control section 171. In graph shown in FIG. 19, the horizontal axisshows the coordinates of the screen shown by the organic EL displaypanel 200, and the vertical axis shows the gain. As shown in FIG. 19,the control of the shading ratio for the screen peripheral part is acontrol so that the gain at the screen peripheral part becomes smallerthan that at the screen central portion. Also, the gain for the screenperipheral part becomes smaller by the application of the gain Ksh_base,when the degree of risk or the degree of stillness increases. This is acontrol of the shading ratio for the screen peripheral part, by the gainKsh_base calculated by the luminance suppression gain control section171.

Note that, the luminance control for a screen peripheral part shown inFIG. 19 is performed for at least one of the vertical direction or thehorizontal direction. Further, the shading ratio for the screenperipheral part may be independently set for each of the horizontaldirection and the vertical direction.

FIG. 20 is an explanatory diagram which shows an example of a shadingshape stored in the original signal component shading gain LUT 173. Theimage persistence prevention control section 104 retains a gain whichuses a shape such as shown in FIG. 20 in the original signal componentshading gain LUT 173, and performs luminance control for the screenperipheral part by subtracting this gain from 1. The luminance controlfor the screen peripheral part is represented by the following equation.In the following equation, G_(SH) is a gain for luminance control forthe screen peripheral part, LUT is a gain stored in the original signalcomponent shading gain LUT 173, and riskpeak_frm is the maximum value ofthe degree of risk for the screen peripheral part in the risk mapgenerated by the risk and stillness detection section 110.

G _(SH)=1−LUT*Ksh_base(riskpeak_frm)

Note that, since the gain Ksh_base can take a value equal to or morethan 1, there are cases where G_(SH) can become a negative value in theabove described equation. The luminance suppression gain control section171 performs a clipping process in which G_(SH) will be 0 in the casewhere G_(SH) becomes a negative value.

FIG. 21 is an explanatory diagram which shows a graph used whenobtaining the gain Ksh_base by the luminance suppression gain controlsection 171. In the graph shown in FIG. 21, the horizontal axis is themaximum value of the degree of risk for the screen peripheral part inthe risk map generated by the risk and stillness detection section 110,and the vertical axis is the gain Ksh_base.

In the case where the maximum value for the screen peripheral part inthe risk map is equal to or less than a prescribed value Ksh_STT, suchas in the graph shown in FIG. 21, the luminance suppression gain controlsection 171 outputs the gain Ksh_base as a prescribed value Ksh1. Also,when the maximum value for the screen peripheral part in the risk mapexceeds the prescribed value Ksh_STT, the luminance suppression gaincontrol section 171 outputs the gain Ksh_base raised from Ksh1. Theluminance suppression gain control section 171 raises the gain Ksh_basefrom Ksh1 so that the inclination becomes +m.

Also, when the maximum value for the screen peripheral part in the riskmap becomes a prescribed value Ksh_END, the luminance suppression gaincontrol section 171 stops the rise of the gain Ksh_base, and thereafteroutputs the same value even if the maximum value for the screenperipheral part in the risk map exceeds Ksh_END.

Heretofore, a calculation of the gain Ksh_base for controlling theshading ratio for a screen peripheral part, by the luminance suppressiongain control section 171, has been described. Next, a calculation of thegain Gpoff for weakening the gain when performing the raising process ofthe luminance control section 103, by the luminance suppression gaincontrol section 171, will be described.

The organic EL display panel 200 according to an embodiment of thepresent disclosure is a display panel which displays images with thefour colors R, G, B, W. In the case where a video has a high luminance,a clear image can be displayed on the organic EL display panel 200 byraising the high luminance side to a higher luminance. FIG. 22 is anexplanatory diagram which shows, by a graph, a state in which a highluminance side of a video signal having a linear characteristic israised to a higher luminance.

Here, a raising process by the luminance control section 103 will bedescribed. An HSV/HSL conversion section 182 included in the luminancecontrol section 103 converts a video signal supplied to the luminancecontrol section 103 into a hue H, a saturation S, a lightness V, or aluminance L. A raising gain LUT 183 refers to the saturation S, thelightness V or the luminance L output by the HSV/HSL conversion section182, and outputs a gain Gv/Gs for the hue component, the lightnesscomponent, or the luminance component. A large area detection section184 detects an area of a white image within the screen in block unitswhich have a prescribed size, for the lightness V or the luminance Loutput by the HSV/HSL conversion section 182, and outputs a gain Gareacorresponding to the area. The multiplier 185 multiplies the gain Gv/Gsby the gain Garea and outputs the multiplication result, and the adder186 adds 1.10 to the output of the multiplier 185, and outputs theaddition result.

Further, the luminance gain calculation section 187 included in theluminance control section 103 outputs a gain Gbase by referring to alook-up table, from the average luminance value of the video signalsupplied to the luminance control section 103. The gain Gbase becomes again Gup by multiplying by the output of the adder 186 at the multiplier189 after passing through the IIR filter 188. The high luminance side ofthe video signal supplied to the luminance control section 103 is raisedto a higher luminance, by having the gain Gup multiplied at themultipliers 190 a, 190 b and 190 c.

However, when the high luminance side is raised to a higher luminance ata position where the degree of risk or the degree of stillness is high,an image persistence phenomenon is likely to occur at the pixels of thisposition. Therefore, it is desirable to lower the raising amount at theposition where the degree of risk or the degree of stillness is high,such as shown in FIG. 22, or to not perform this raising. The gain Gpoffcalculated by the luminance suppression gain control section 171 is usedto control this raising.

FIG. 23 is an explanatory diagram which shows a graph used whenobtaining the gain Gpoff by the luminance suppression gain controlsection 171. In the graph shown in FIG. 23, the horizontal axis is themaximum value of the degree of risk for the entire screen in the riskmap generated by the risk and stillness detection section 110, and thevertical axis is the gain Gpoff.

As shown in the graph shown in FIG. 23, in the case where the maximumvalue of the degree of risk for the entire screen in the risk map isequal to or less than a prescribed value riskstt1, the luminancesuppression gain control section 171 outputs the gain Gpoff as aprescribed value gpoff_ini. Also, when the maximum value of the degreeof risk for the entire screen in the risk map exceeds the prescribedvalue riskstt1, the luminance suppression gain control section 171outputs the gain Gpoff lowered from gpoff_ini. The luminance suppressiongain control section 171 lowers the gain Gpoff from gpoff_ini so thatthe inclination becomes −a.

Also, when the maximum value of the degree of risk for the entire screenin the risk map becomes a prescribed value riskend1, the luminancesuppression gain control section 171 stops the reduction of the gainGpoff, and thereafter outputs the same value even if the maximum valueof the degree of risk for the entire screen in the risk map exceedsriskend1. The process which calculates the gain Gpoff by the luminancesuppression gain control section 171 is represented by the followingequation.

if (riskpeak<riskstt1)Gpoff=gpoff_(—) ini

elseif (riskpeak<riskend1)Gpoff=gpoff_(—) ini−a*(riskpeak−riskstt1)

else Gpoff=gpoff_(—) ini−a*(riskend1−riskstt1)

Note that while a case has been mentioned in the above description whichuses a risk map, the luminance suppression gain control section 171calculates a similar gain by using a stillness map or a risk map forpartial control. Also, the luminance suppression gain control section171 compares, by pixel units, the gain Gpoff obtained by using the riskmap, the gain Gpoff obtained by using the stillness map, and the gainGpoff obtained by using the risk map for partial control, and outputsthe lowest gain to the multiplier 177.

The luminance suppression gain control section 171 may perform acalculation so that the range of the gain Gpoff is changed from 0 timesto 1 time, or may perform a calculation so that the range is changedfrom −1 time to 1 time. In the case where the range of the gain Gpoff ischanged from 0 times to 1 time, the raising is canceled in the highluminance side of the input video signal. On the other hand, in the casewhere the range of the gain Gpoff is changed from −1 time to 1 time, notonly is the raising canceled in the high luminance side of the inputvideo signal, but also the luminance of the high luminance side of theinput video signal is suppressed.

The gain Ksh_peak is a gain to be reflected in the gain Gpoff and forcontrolling the shading ratio of the screen peripheral part. By havingthe gain Ksh_peak multiplied together with the gain Gpoff, the luminancecontrol section 103 can cancel the raising for the screen peripheralpart being greater than that of the screen central part. The luminancesuppression gain control section 171 executes a calculation of the gainKsh_peak similar to the calculation of the above described gainKsh_base.

Heretofore, a calculation of the gain Gpoff for weakening the gain whenperforming the raising process by the luminance control section 103, bythe luminance suppression gain control section 171, has been described.Next, a process of the IIR filter 176 included in the image persistenceprevention control section 104 will be described.

The threshold th, and the gains Gall, Gpoff, Ksh_base and Ksh_peakgenerated by the luminance suppression gain control section 171 are sentto the IIR filter 176. The IIR filter 176 suppresses sudden changes ofthe threshold th, and the gains Gall, Gpoff, Ksh_base and Ksh_peak. Thedegree of risk and the degree of stillness are gradually counted up inthe risk and stillness detection section 110, and are rapidly cancelledin the risk and stillness detection section 110 when a different imageis input once.

However, when the degree of risk and the degree of stillness are rapidlycancelled when releasing the threshold and gain control, rapid changesof luminance may occur when an image is displayed on the organic ELdisplay panel 200. Therefore, the IIR filter 176 is a filter forgradually changing the threshold or the gain. The process of the IIRfilter 176 is represented by the following equation. In the followingequation, X_(n) represents the input of the current time, Y_(n)represents the output of the current time, Y_(n-1) represents the outputof a previous time, and K represents the feedback ratio.

K=(1−K)*X _(n) +K*Y _(n-1)

Y _(n) =X _(n) +K*(Y _(n-1) −X _(n))

FIG. 24 is an explanatory diagram which shows a configuration example ofthe IIR filter 176. As shown in FIG. 24, the IIR filter 176 includes adelay section 201, adders 202 and 204, and a multiplier 203.

The delay section 201 outputs an output of the adder 204 to the adder202 delayed by one frame. The adder 202 subtracts the input of thecurrent time X_(n) from the output of 1 time previous Y_(n-1), andoutputs the subtraction result to the multiplier 203. The multiplier 203multiplies the prescribed feedback ration K by the output of the adder202, and outputs the multiplication result. The adder 204 adds theoutput of the multiplier 203 to the input of the current time X_(n), andoutputs the addition result as the output of the current time Y_(n).

Heretofore, the process of the IIR filter 176 included in the imagepersistence prevention control section 104 has been described. Up tohere, examples of luminance control and image persistence preventioncontrol have been described. To continue, next, a WRGB conversionprocess by the WRGB conversion section 105, using the risk map forpartial control generated by the risk and stillness detection section110, will be described.

[Example of the WRGB Conversion Process Using a Risk Map for PartialControl]

As described above, the organic EL display panel 200 according to anembodiment of the present disclosure is a display panel which displaysan image with the four colors R, G, B, W. Since a video signal issupplied with only the three colors R, G, B, it may be necessary togenerate a signal, from this video signal, in order to supply W pixels.The WRGB conversion section 105 is a section for executing a WRGBconversion process which generates a signal from the video signal of thethree colors R, G, B in order to supply W pixels.

For example, in the case where the input video signal is a video signalwhich displays a white image, when the video signal is converted so thatonly W pixels emit light, the power consumption can be suppressed sincethe pixels of the other colors are not emitting light. However, whenonly the W pixels emit light, deterioration of the W pixels will beintense when compared to that of the pixels of other colors. Therefore,in the case where the input video signal is a video signal whichdisplays a white image, by executing a WRGB conversion process for thevideo signal so that the pixels of other colors are also used, the WRGBconversion section 105 can suppress the deterioration of the W pixels.The conversion process by the WRGB conversion section 105 is expressedby the following equation.

$\begin{pmatrix}{Rout} \\{Gout} \\{Bout}\end{pmatrix} = {\begin{pmatrix}{Rin} \\{Gin} \\{Bin}\end{pmatrix} - {{Wout}*\begin{pmatrix}{Kr} \\{Kg} \\{Kb}\end{pmatrix}}}$${Wout} = {{Gw}*{{MIN}\left( {\frac{Rin}{Kr},\frac{Gin}{Kg},\frac{Bin}{Kb}} \right)}}$

R_(in), G_(in) and B_(in) represent the signal levels of each of thecolors R, G, B input to the WRGB conversion section 105, and R_(out),G_(out), B_(out) and W_(out) represent the signal levels of each of thecolors R, G, B, W output from the WRGB conversion section 105. Further,K_(r), K_(g) and K_(b) are coefficients by each of the colors R, G, Bwhich contribute to the white color signal, and Gw is a gain (Wconversion coefficient) provided to the white color signal. K_(r), K_(g)and K_(b) can be obtained by the following matrix equation. X, Y and Zare tri-stimulus values. Note that, it is desirable that the inversematrix on the right side of the following equation is used for thecalculation of K_(r), K_(g) and K_(b) in a calculation performed inadvance.

$\begin{pmatrix}K_{r} \\K_{g} \\K_{b}\end{pmatrix} = {\begin{pmatrix}X_{WR} & X_{WG} & X_{WB} \\Y_{WR} & Y_{WG} & Y_{WB} \\Z_{WR} & Z_{WG} & Z_{WB}\end{pmatrix}^{- 1}\begin{pmatrix}X_{W} \\Y_{W} \\Z_{W}\end{pmatrix}}$

In the present embodiment, the WRGB conversion section 105 controls thevalue of the gain Gw, by using the risk map for partial controlgenerated by the risk and stillness detection section 110. By using therisk map for partial control, the WRGB conversion section 105 can lowerthe value of the gain Gw for locations at which the degree of risk ishigh.

FIG. 25 is an explanatory diagram which shows a configuration example ofthe WRGB conversion section 105 according to an embodiment of thepresent disclosure. As shown in FIG. 25, the WRGB conversion section 105according to an embodiment of the present disclosure includes areciprocal calculation section 211, multipliers 212, 215 and 216, aminimum value selection section 213, a gain calculation section 214, anda subtractor 217.

The reciprocal calculation section 211 calculates a reciprocal of thecoefficients K_(r), K_(g) and K_(b), and outputs the calculation resultto the multiplier 212. The multiplier 212 multiplies the input level ofeach of the colors R, G, B by the reciprocal of the coefficients K_(r),K_(g) and K_(b), and outputs the multiplication result to the minimumvalue selection section 213. The minimum value selection section 213selects a minimum value Worg from among the output values from themultiplier 212, and outputs this minimum value to the gain calculationsection 214 and the multiplier 215.

The gain calculation section 214 performs a calculation of the gain Gwby using the output Worg of the minimum value selection section 213, andoutputs the calculated gain Gw to the multiplier 215. Further, the gaincalculation section 214 controls the value of the output gain Gw, byusing the risk map for partial control generated by the risk andstillness detection section 110. The multiplier 215 sets, as an outputof W, the result of the gain calculation section 214 multiplying thegain Gw by the output of the minimum value selection section 213, andoutputs this output of W to the multiplier 216.

The multiplier 216 multiplies the output of the multiplier 215 by eachof the coefficients K_(r), K_(g) and K_(b), and outputs themultiplication result. The subtractor 217 subtracts each of the outputsof the multiplier 216 from the input level of each of the colors R, G,B, and outputs the subtraction result. By having a configuration such asshown in FIG. 25, the WRGB conversion section 105 according to anembodiment of the present disclosure can convert an input video signalof RGB into a video signal of RGBW, and can output the converted videosignal.

To continue, a configuration example of the gain calculation section 214included in the WRGB conversion section 105 according to an embodimentof the present disclosure will be described. FIG. 26 is an explanatorydiagram which shows a configuration example of the gain calculationsection 214. Hereinafter, a configuration example of the gaincalculation section 214 will be described by using FIG. 26.

As shown in FIG. 26, the gain calculation section 214 included in theWRGB conversion section 105 according to an embodiment of the presentdisclosure includes a gradation-dependent gain calculation section 221,a risk-linked gain calculation section 223, and a minimum valueselection section 224.

The gradation-dependent gain calculation section 221 outputs a gain Gw1by referring to a look-up table retained within, or external to, thegradation-dependent gain calculation section 221, by using the outputWorg of the minimum value selection section 213. FIG. 27 is anexplanatory diagram which shows an example of a look-up table referredto by the gradation-dependent gain calculation section 221. FIG. 27shows, by a graph, a look-up table referred to by thegradation-dependent gain calculation section 221. In the graph shown inFIG. 27, the horizontal axis is the output Worg of the minimum valueselection section 213, and the vertical axis is the output gain Gw1which can take values from 0 times up to 1.0 time.

The risk-linked gain calculation section 223 calculates and outputs again Gw3 by using the risk map for partial control generated by the riskand stillness detection section 110. FIG. 28 is an explanatory diagramwhich shows a graph used when obtaining the gain Gw3 by the risk-linkedgain calculation section 223. In the graph shown in FIG. 28, thehorizontal axis is the maximum value of the degree of risk in the riskmap for partial control generated by the risk and stillness detectionsection 110, and the vertical axis is the gain Gw3.

In the case where the maximum value of the degree of risk in the riskmap for partial control is equal to or less than a prescribed valueriskstt4, such as in the graph shown in FIG. 28, the risk-linked gaincalculation section 223 outputs the gain Gw3 as a prescribed valueGw_max. Also, when the maximum value of the degree of risk in the riskmap for partial control exceeds the prescribed value riskstt4, therisk-linked gain calculation section 223 outputs the gain Gw3 loweredfrom Gw_max. The risk-linked gain calculation section 223 lowers thegain Gw3 from Gw_max so that the inclination becomes −n.

Also, when the maximum value of the degree of risk in the risk map forpartial control becomes a prescribed value riskend4, the risk-linkedgain calculation section 223 stops the reduction of the gain Gw3, andthereafter outputs the same value even if the maximum value of thedegree of risk in the risk map for partial control exceeds riskend4.

The minimum value selection section 224 selects the minimum value fromamong the gain Gw1 output by the gradation-dependent gain calculationsection 221 and the gain Gw3 output by the risk-linked gain calculationsection 223, and outputs this minimum value as the gain Gw.

By having a configuration such as shown in FIG. 26, it becomes possiblefor the gain calculation section 214 included in the WRGB conversionsection 105 according to an embodiment of the present disclosure toperform a calculation process of the gain Gw using the risk map forpartial control. By calculating the gain Gw by using the risk map forpartial control, the gain calculation section 214 can reduce the gain Gwfor regions at which the degree of risk is high.

Note that while the gradation-dependent gain calculation section 221 hasbeen described when the gain Gw1 is output by referring to the look-uptable shown in FIG. 27, the gain Gw1 may be output by referring toanother look-up table in addition to the look-up table shown in FIG. 27.

In the case where secular variations or temperature variations ofchromaticity at a low gradation side are predominant in the W pixels, itbecomes possible for the WRGB conversion section 105 to perform displayin a state in which the variations of chromaticity are suppressed, byexpressing white with the pixels of the three colors RGB in the case ofa low gradation. Here, a low gradation is a gradation corresponding to10nit, for example.

The chromatic variations of the W pixels depend on the current density.When current deterioration of each pixel is disregarded, the chromaticvariations of the W pixels depend on the gradation of a linear space.Accordingly, by limiting a conversion coefficient at a low gradationside, it becomes possible for the WRGB conversion section 105 to performdisplay in a state in which the variations of chromaticity aresuppressed.

FIG. 29 is an explanatory diagram which shows an example of a look-uptable referred to by the gradation-dependent gain calculation section221. A look-up table for limiting a conversion coefficient at a lowgradation side is shown in FIG. 29 in addition to the look-up tablerepresented by the graph shown in FIG. 27. The reference numeral 231 isthe above described look-up table represented by the graph shown in FIG.27, and the reference numeral 232 is a look-up table for suppressingchromatic variations at a low luminance side. The gradation-dependentgain calculation section 221 refers to the two look-up tables by usingthe input Worg, selects the smallest value of the values represented bythe dotted line in FIG. 29, and outputs this smallest value as the gainGw1.

Heretofore, a calculation process of the gain Gw using the risk map forpartial control has been described. By calculating such a gain Gw, theWRGB conversion section 105 according to an embodiment of the presentdisclosure can reduce the value of the gain Gw for locations at whichthe degree of risk is high.

2. CONCLUSION

When a video signal is supplied so that the same pixels of the organicEL display panel 200 continue to emit light at a high luminance, whendisplaying a video on the organic EL display panel 200, theself-luminous display device 10 according to an embodiment of thepresent disclosure such as described above lowers the luminance for thisvideo signal at the time when light is emitted by the organic EL displaypanel 200, and generates a risk map or a stillness map which isinformation for preventing the generation of an image persistencephenomenon.

The self-luminous display device 10 according to an embodiment of thepresent disclosure calculates a gain for reducing luminance, for theentire screen or for a portion of the screen, by using the risk map orthe stillness map generated for preventing the generation of an imagepersistence phenomenon, and applies this gain to the video signal.

By calculating a risk map or a stillness map such as described above,and by performing a calculation of a gain using this risk map or thisstillness map, the self-luminous display device 10 according to anembodiment of the present disclosure can execute appropriate luminancecontrol in the case where some video signal is supplied in which thereis a concern of an image persistence phenomenon occurring, and canprevent the generation of an image persistence phenomenon.

Further, the self-luminous display device 10 according to an embodimentof the present disclosure can generate a risk map for partial control inorder to execute luminance control for a portion of the screen, such asdescribed above. By generating a risk map for partial control, theself-luminous display device 10 according to an embodiment of thepresent disclosure can lower the luminance for regions in which there isthe possibility of an image persistence phenomenon occurring, and candisplay a video on the organic EL display panel 200 in which there is nosense of discomfort on the entire screen.

Note that in the case where the self-luminous display device 10according to an embodiment of the present disclosure displays a videowith only the pixels of the three colors RGB, the WRGB conversionsection 105 may not be included in the display control section 100.

Further, a computer program for causing hardware, such as a CPU, ROM andRAM built-into each apparatus, to exhibit functions similar to theconfigurations of each of the above described apparatuses can becreated. Further, a storage medium storing this computer program canalso be provided. Further, a series of processes can be executed withthe hardware, by configuring each of the functional blocks shown by thefunctional block figures with the hardware.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

For example, the luminance control section 103 and the image persistenceprevention control section 104 may automatically switch a control forthe video signal, in accordance with the type of information displayedon the organic EL display panel 200. For example, in the case where adata broadcast including text, images or the like is displayed on a partof the organic EL display panel 200, the image persistence preventioncontrol section 104 may execute a control so as to change the gainapplied at the portion on which the video is displayed and at theportion on which the data broadcast is displayed.

Further, for example, the luminance control section 103 and the imagepersistence prevention control section 104 may perform luminance controlby using a peak of the degree of risk for the entire screen, by theabove description, or may perform similar luminance control by using apeak of the degree of risk for a portion of the screen. For example, theprocess in the luminance control section 103 which cancels a gain forraising a high luminance side may not only use a peak of the degree ofrisk for the entire screen, but may also use a peak of the degree ofrisk for a portion of the screen.

Additionally, the present technology may also be configured as below.

(1) A self-luminous display device including:

a data calculation section configured to calculate, by using a suppliedvideo signal, data relating to a luminance amount accumulated in a unitof a first block in a target region for luminance control in a screen onwhich a plurality of pixels are arranged in a matrix, each of the pixelsincluding a light emitting element which emits light by itself inaccordance with a current amount;

a resampling section configured to resample the data relating to theluminance amount in the target region, in a unit of a second block, thedata relating to the luminance amount being calculated by the datacalculation section, the second block being larger than the first block;and

a scaling section configured to generate data for luminance control inthe target region by scaling the data resampled by the resamplingsection in the unit of first block.

(2) The self-luminous display device according to (1),

wherein the resampling section searches for a maximum value in a givensecond block and a second block surrounding the given second block, atthe time when resampling the data relating to the luminance amount.

(3) The self-luminous display device according to (1) or (2), furtherincluding:

a video signal control section configured to generate a gain for thetarget region by using the data for luminance control generated by thescaling section, the gain canceling a gain applied to a high luminanceside of the video signal.

(4) The self-luminous display device according to any one of (1) to (3),further including:

a video signal control section configured to generate a gain for thetarget region by using the data for luminance control generated by thescaling section, the gain lowering a luminance of a high luminance sideof the video signal.

(5) The self-luminous display device according to any one of (1) to (4),further including:

a video signal control section configured to control a conversion ratiofor the target region when generating a video signal to be supplied to awhite pixel from video signals of red, green and blue by using the datafor luminance control generated by the scaling section.

(6) The self-luminous display device according to any one of (1) to (5),further including:

a video signal control section configured to generate a gain applied tothe video signal by using data relating to the luminance amountcalculated for a partial region of the screen by the data calculationsection.

(7) The self-luminous display device according to any one of (1) to (6),further including:

a maximum value detection section configured to detect a maximum valueof the data relating to the luminance amount at only a prescribed regionof a periphery of the screen for the data relating to the luminanceamount generated by the data calculation section.

(8) The self-luminous display device according to (7), furtherincluding:

a video signal control section configured to control a gain applied tothe prescribed region by using information of the maximum value detectedat the prescribed region of the periphery of the screen by the maximumvalue detection section.

(9) The self-luminous display device according to any one of (1) to (8),further including:

a luminance determination section configured to cause the datacalculation section to calculate the data relating to the luminanceamount in a case where the video signal is equal to or more than aprescribed luminance,

wherein the luminance determination section judges whether or not amaximum value of a luminance of a white color generated from videosignals of red, green and blue, and a maximum value of a luminance of amonochromic color, are equal to or more than a prescribed luminance

(10) A self-luminous display device including:

a data calculation section configured to calculate data relating to aluminance amount accumulated in a unit of a first block in a targetregion for luminance control in a screen on which a plurality of pixelsare arranged in a matrix and an image is displayed with a red pixel, agreen pixel, a blue pixel, and a white pixel, each of the pixelsincluding a light emitting element which emits light by itself inaccordance with a current amount; and

a signal processing section configured to execute signal processing on avideo signal supplied to the screen based on a peak of the data relatingto the luminance amount calculated by the data calculation section.

(11) The self-luminous display device according to (10),

wherein the signal processing section executes signal processing togenerate a gain for the target region by using the data relating to theluminance amount calculated by the data calculation section, the gaincanceling a gain applied to a high luminance side of the video signal.

(12) The self-luminous display device according to (10) or (11),

wherein the signal processing section executes signal processing togenerate a gain for the target region by using the data relating to theluminance amount calculated by the data calculation section, the gainlowering a luminance of a high luminance side of the video signal.

(13) The self-luminous display device according to any one of (10) to(12),

wherein the signal processing section executes signal processing tocontrol a conversion ratio for the target region when generating a videosignal to be supplied the white pixel from video signals of red, greenand blue by using the data relating to the luminance amount calculatedby the data calculation section.

(14) The self-luminous display device according to any one of (10) to(13),

wherein the signal processing section executes signal processing on thevideo signal by using data for luminance control on a portion of thescreen which is generated from the data relating to the luminance amountin the target region, the data relating to the luminance amount beingcalculated by the data calculation section.

(15) The self-luminous display device according to any one of (10) to(14),

wherein the signal processing section executes signal processing togenerate a gain for the target region by using the data relating to theluminance amount calculated by the data calculation section, the gainuniformly controlling a luminance of a whole of the screen.

(16) The self-luminous display device according to (10),

wherein the signal processing section executes signal processing on thevideo signal supplied to the screen based on a peak of the data relatingto the luminance amount detected at only a prescribed region of aperiphery of the screen.

(17) The self-luminous display device according to (16),

wherein the signal processing section executes signal processing tocontrol a gain applied to the prescribed region.

(18) The self-luminous display device according to (16) or (17),

wherein the signal processing section executes signal processing togenerate a gain for the target region by using the data relating to theluminance amount calculated by the data calculation section, the gaincanceling a gain applied to a high luminance side of the video signal.

(19) The self-luminous display device according to any one of (16) to(18),

wherein the signal processing section executes signal processing togenerate a gain for the target region by using the data relating to theluminance amount calculated by the data calculation section, the gainlowering a luminance of a high luminance side of the video signal.

(20) The self-luminous display device according to any one of (16) to(19),

wherein the signal processing section executes signal processing togenerate a gain for the target region by using the data relating to theluminance amount calculated by the data calculation section, the gainuniformly controlling a luminance of a whole of the target region.

(21) A method for controlling a self-luminous display device, the methodincluding:

calculating, by using a supplied video signal, data relating to aluminance amount accumulated in a unit of a first block in a targetregion for luminance control in a screen on which a plurality of pixelsare arranged in a matrix, each of the pixels including a light emittingelement which emits light by itself in accordance with a current amount;

resampling the data relating to the luminance amount in the targetregion, in a unit of a second block, the data relating to the luminanceamount being calculated in the data calculation step, the second blockbeing larger than the first block; and

generating data for luminance control in the target region by scalingthe data resampled in the resampling step in the unit of first block.

(22) A method for controlling a self-luminous display device, the methodincluding:

calculating data relating to a luminance amount accumulated in a unit ofa first block in a target region for luminance control in a screen onwhich a plurality of pixels are arranged in a matrix and an image isdisplayed with a red pixel, a green pixel, a blue pixel, and a whitepixel, each of the pixels including a light emitting element which emitslight by itself in accordance with a current amount; and

executing signal processing on a video signal supplied to the screenbased on a peak of the data relating to the luminance amount calculatedin the data calculation step.

What is claimed is:
 1. A self-luminous display device comprising: a data calculation section configured to calculate, by using a supplied video signal, data relating to a luminance amount accumulated in a unit of a first block in a target region for luminance control in a screen on which a plurality of pixels are arranged in a matrix, each of the pixels including a light emitting element which emits light by itself in accordance with a current amount; a resampling section configured to resample the data relating to the luminance amount in the target region, in a unit of a second block, the data relating to the luminance amount being calculated by the data calculation section, the second block being larger than the first block; and a scaling section configured to generate data for luminance control in the target region by scaling the data resampled by the resampling section in the unit of first block.
 2. The self-luminous display device according to claim 1, wherein the resampling section searches for a maximum value in a given second block and a second block surrounding the given second block, at the time when resampling the data relating to the luminance amount.
 3. The self-luminous display device according to claim 1, further comprising: a video signal control section configured to generate a gain for the target region by using the data for luminance control generated by the scaling section, the gain canceling a gain applied to a high luminance side of the video signal.
 4. The self-luminous display device according to claim 1, further comprising: a video signal control section configured to generate a gain for the target region by using the data for luminance control generated by the scaling section, the gain lowering a luminance of a high luminance side of the video signal.
 5. The self-luminous display device according to claim 1, further comprising: a video signal control section configured to control a conversion ratio for the target region when generating a video signal to be supplied to a white pixel from video signals of red, green and blue by using the data for luminance control generated by the scaling section.
 6. The self-luminous display device according to claim 1, further comprising: a video signal control section configured to generate a gain applied to the video signal by using data relating to the luminance amount calculated for a partial region of the screen by the data calculation section.
 7. The self-luminous display device according to claim 1, further comprising: a maximum value detection section configured to detect a maximum value of the data relating to the luminance amount at only a prescribed region of a periphery of the screen for the data relating to the luminance amount generated by the data calculation section.
 8. The self-luminous display device according to claim 7, further comprising: a video signal control section configured to control a gain applied to the prescribed region by using information of the maximum value detected at the prescribed region of the periphery of the screen by the maximum value detection section.
 9. The self-luminous display device according to claim 1, further comprising: a luminance determination section configured to cause the data calculation section to calculate the data relating to the luminance amount in a case where the video signal is equal to or more than a prescribed luminance, wherein the luminance determination section judges whether or not a maximum value of a luminance of a white color generated from video signals of red, green and blue, and a maximum value of a luminance of a monochromic color, are equal to or more than a prescribed luminance.
 10. A self-luminous display device comprising: a data calculation section configured to calculate data relating to a luminance amount accumulated in a unit of a first block in a target region for luminance control in a screen on which a plurality of pixels are arranged in a matrix and an image is displayed with a red pixel, a green pixel, a blue pixel, and a white pixel, each of the pixels including a light emitting element which emits light by itself in accordance with a current amount; and a signal processing section configured to execute signal processing on a video signal supplied to the screen based on a peak of the data relating to the luminance amount calculated by the data calculation section.
 11. The self-luminous display device according to claim 10, wherein the signal processing section executes signal processing to generate a gain for the target region by using the data relating to the luminance amount calculated by the data calculation section, the gain canceling a gain applied to a high luminance side of the video signal.
 12. The self-luminous display device according to claim 10, wherein the signal processing section executes signal processing to generate a gain for the target region by using the data relating to the luminance amount calculated by the data calculation section, the gain lowering a luminance of a high luminance side of the video signal.
 13. The self-luminous display device according to claim 10, wherein the signal processing section executes signal processing to control a conversion ratio for the target region when generating a video signal to be supplied the white pixel from video signals of red, green and blue by using the data relating to the luminance amount calculated by the data calculation section.
 14. The self-luminous display device according to claim 10, wherein the signal processing section executes signal processing on the video signal by using data for luminance control on a portion of the screen which is generated from the data relating to the luminance amount in the target region, the data relating to the luminance amount being calculated by the data calculation section.
 15. The self-luminous display device according to claim 10, wherein the signal processing section executes signal processing to generate a gain for the target region by using the data relating to the luminance amount calculated by the data calculation section, the gain uniformly controlling a luminance of a whole of the screen.
 16. The self-luminous display device according to claim 10, wherein the signal processing section executes signal processing on the video signal supplied to the screen based on a peak of the data relating to the luminance amount detected at only a prescribed region of a periphery of the screen.
 17. The self-luminous display device according to claim 16, wherein the signal processing section executes signal processing to control a gain applied to the prescribed region.
 18. The self-luminous display device according to claim 16, wherein the signal processing section executes signal processing to generate a gain for the target region by using the data relating to the luminance amount calculated by the data calculation section, the gain canceling a gain applied to a high luminance side of the video signal.
 19. The self-luminous display device according to claim 16, wherein the signal processing section executes signal processing to generate a gain for the target region by using the data relating to the luminance amount calculated by the data calculation section, the gain lowering a luminance of a high luminance side of the video signal.
 20. The self-luminous display device according to claim 16, wherein the signal processing section executes signal processing to generate a gain for the target region by using the data relating to the luminance amount calculated by the data calculation section, the gain uniformly controlling a luminance of a whole of the target region. 